package org.apache.maven.plugin;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.maven.artifact.ArtifactUtils;
import org.apache.maven.model.Plugin;
import org.apache.maven.plugin.descriptor.MojoDescriptor;
import org.apache.maven.plugin.descriptor.PluginDescriptor;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.component.repository.ComponentDescriptor;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.repository.LocalRepository;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.repository.WorkspaceRepository;

/**
 * Caches raw plugin descriptors. A raw plugin descriptor is a descriptor that has just been
 * extracted from the plugin artifact and does not contain any runtime specific data. The cache must
 * not be used for descriptors that hold runtime data like the plugin realm.
 * <strong>Warning:</strong> This is an internal utility interface that is only public for technical
 * reasons, it is not part of the public API. In particular, this interface can be changed or
 * deleted without prior notice.
 * 
 * @since 3.0
 * @author Benjamin Bentmann
 */
@Component(role = PluginDescriptorCache.class)
public class DefaultPluginDescriptorCache implements PluginDescriptorCache {

  private Map<Key, PluginDescriptor> descriptors = new HashMap<Key, PluginDescriptor>(128);

  public void flush() {
    descriptors.clear();
  }

  public Key createKey(Plugin plugin, List<RemoteRepository> repositories, RepositorySystemSession session) {
    return new CacheKey(plugin, repositories, session);
  }

  public PluginDescriptor get(Key cacheKey) {
    return clone(descriptors.get(cacheKey));
  }

  public void put(Key cacheKey, PluginDescriptor pluginDescriptor) {
    descriptors.put(cacheKey, clone(pluginDescriptor));
  }

  protected static PluginDescriptor clone(PluginDescriptor original) {
    PluginDescriptor clone = null;

    if (original != null) {
      clone = new PluginDescriptor();

      clone.setGroupId(original.getGroupId());
      clone.setArtifactId(original.getArtifactId());
      clone.setVersion(original.getVersion());
      clone.setGoalPrefix(original.getGoalPrefix());
      clone.setInheritedByDefault(original.isInheritedByDefault());

      clone.setName(original.getName());
      clone.setDescription(original.getDescription());
      clone.setRequiredMavenVersion(original.getRequiredMavenVersion());

      clone.setPluginArtifact(ArtifactUtils.copyArtifactSafe(original.getPluginArtifact()));

      clone.setComponents(clone(original.getMojos(), clone));
      clone.setId(original.getId());
      clone.setIsolatedRealm(original.isIsolatedRealm());
      clone.setSource(original.getSource());

      clone.setDependencies(original.getDependencies());
    }

    return clone;
  }

  private static List<ComponentDescriptor<?>> clone(List<MojoDescriptor> mojos, PluginDescriptor pluginDescriptor) {
    List<ComponentDescriptor<?>> clones = null;

    if (mojos != null) {
      clones = new ArrayList<ComponentDescriptor<?>>(mojos.size());

      for (MojoDescriptor mojo : mojos) {
        MojoDescriptor clone = mojo.clone();
        clone.setPluginDescriptor(pluginDescriptor);
        clones.add(clone);
      }
    }

    return clones;
  }

  private static final class CacheKey implements Key {

    private final String groupId;

    private final String artifactId;

    private final String version;

    private final WorkspaceRepository workspace;

    private final LocalRepository localRepo;

    private final List<RemoteRepository> repositories;

    private final int hashCode;

    public CacheKey(Plugin plugin, List<RemoteRepository> repositories, RepositorySystemSession session) {
      groupId = plugin.getGroupId();
      artifactId = plugin.getArtifactId();
      version = plugin.getVersion();

      workspace = CacheUtils.getWorkspace(session);
      localRepo = session.getLocalRepository();
      this.repositories = new ArrayList<RemoteRepository>(repositories.size());
      for (RemoteRepository repository : repositories) {
        if (repository.isRepositoryManager()) {
          this.repositories.addAll(repository.getMirroredRepositories());
        } else {
          this.repositories.add(repository);
        }
      }

      int hash = 17;
      hash = hash * 31 + groupId.hashCode();
      hash = hash * 31 + artifactId.hashCode();
      hash = hash * 31 + version.hashCode();
      hash = hash * 31 + hash(workspace);
      hash = hash * 31 + localRepo.hashCode();
      hash = hash * 31 + CacheUtils.repositoriesHashCode(repositories);
      this.hashCode = hash;
    }

    @Override
    public int hashCode() {
      return hashCode;
    }

    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }

      if (!(obj instanceof CacheKey)) {
        return false;
      }

      CacheKey that = (CacheKey) obj;

      return eq(this.artifactId, that.artifactId) && eq(this.groupId, that.groupId) && eq(this.version, that.version)
          && eq(this.localRepo, that.localRepo) && eq(this.workspace, that.workspace)
          && CacheUtils.repositoriesEquals(this.repositories, that.repositories);
    }

    @Override
    public String toString() {
      return groupId + ':' + artifactId + ':' + version;
    }

    private static int hash(Object obj) {
      return obj != null ? obj.hashCode() : 0;
    }

    private static <T> boolean eq(T s1, T s2) {
      return s1 != null ? s1.equals(s2) : s2 == null;
    }

  }

}
